This application is a continuation patent application of International Application No. PCT/SE01/01168 filed May 23, 2001 which was published in English pursuant to Article 21(2) of the Patent Cooperation Treaty, and which claims priority to Swedish Application No. 0002043-8 filed May 31, 2000. Both applications are expressly incorporated herein by reference in their entireties.
TECHNICAL FIELD: The present invention relates to an arrangement for regulating the rotational speed of a crankshaft included in an internal combustion engine during a gear changing process, as well as a method for regulating the rotational speed of a crankshaft included in an internal combustion engine during a gear changing process of a gearbox connected to the internal combustion engine. More particularly, the invention relates to a method and an arrangement for regulating the rotation axis of a crankshaft included in an internal combustion engine, as well as a gear changing process in a gearbox connected to the internal combustion engine in which the rotational speed of the crankshaft is influenced by the gear ratio in a transmission between the crankshaft and a mass-moment of inertia driven via that transmission. Preferably, a compressor is arranged in connection with the air inlet of the internal combustion engine. The invention also relates to an arrangement for regulating the rotational speed of a shaft driven by an engine during a gear changing process.
BACKGROUND OF THE INVENTION: There is an increased utilization of automatic and semi-automatic gearboxes in commercial vehicles. Such gearboxes function according to the same principle as conventional gearboxes, but with the difference that the gear changing process is performed by means of actuators instead of manually by means of mechanical gear shift levers. FIG. 1 of the accompanying drawings graphically illustrates the principal stages that are passed when changing from a lower to a higher gear in such a gearbox. The diagram in FIG. 1 shows the rotational speed of a crankshaft included in the internal combustion engine as a function of time during a gear changing process. Stage xe2x80x9caxe2x80x9d shows a normal operating condition before a gear changing process is initiated. Stage xe2x80x9cbxe2x80x9d shows torque reduction of the engine after having initiated a gear changing process. Stage xe2x80x9ccxe2x80x9d shows disengagement of a clutch in order to disengage the engine from the gearbox. Stage xe2x80x9cdxe2x80x9d shows reduction of the rotational speed of the crankshaft in order to adapt the crankshaft rotational speed to a new selected gear ratio. Stage xe2x80x9cexe2x80x9d shows renewed engagement of a clutch. Stage xe2x80x9cfxe2x80x9d shows torque increase of the engine, and stage xe2x80x9cgxe2x80x9d once again shows a normal operating condition after having performed a change of a higher gear.
In a similar way, the principal stages that are passed when changing from a higher to a lower gear in such a gearbox are shown in a diagram in FIG. 2. Stage xe2x80x9cgxe2x80x9d shows a normal operating condition before a gear changing process is initiated. Stage xe2x80x9chxe2x80x9d shows torque reduction of the engine after having initiated a gear changing process. Stage xe2x80x9cixe2x80x9d shows disengagement of a clutch in order to disengage the engine from the gearbox. Stage xe2x80x9cjxe2x80x9d shows increase of the rotational speed of the crankshaft in order to adapt the crankshaft rotational speed to a new selected gear ratio. Stage xe2x80x9ckxe2x80x9d shows renewed engagement of a clutch. Stage xe2x80x9clxe2x80x9d shows torque increase of the engine, and stage xe2x80x9cmxe2x80x9d once again shows a normal operating condition after having performed the change of gear to a lower gear.
In order to obtain a vehicle with good running characteristics, it is of importance that a gear changing process is as fast as possible. This is of particular importance when changing a higher gear while a vehicle is being driven uphill, resulting in retardation of travel by gravity on the vehicle. Should the gear changing process be too slow, changing gears will become impossible since the vehicle is retarded to such an extent that a new desired gear will not be suitable once the gear is engaged. Extended gear change processes are also detrimental when changing from a higher to a lower gear. Accordingly, extended gear changing processes result in poor running characteristics and impaired fuel economy.
Accordingly, in order to ensure that a gear changing process is fast, the engine speed should be actively adapted to the engine speed corresponding to the speed of the vehicle and the desired gear ratio during the gear changing process. It is previously known from SE 502 154 to adapt the engine speed by means of applying an exhaust gas brake during a changing-up process, wherein a fast reduction of the engine speed is achieved. This system, however, lacks the possibility to rapidly adapt the engine speed upwards by means of increasing the rotational speed of the engine when downshifting.
From U.S. Pat. No. 5,638,271, a system is known for facilitating the gear changing process of a vehicle by adapting the engine speed when changing from a lower to a higher gear, as well as when changing from a higher to a lower gear. The increase or reduction of the engine speed is performed by means of controlling fuel injection in order to accomplish the desired engine speed. The system according to U.S. Pat. No. 5,638,271, however, lacks an active retardation of the engine speed since the engine speed is reduced solely by means of controlling the fuel injection process.
An object of the present invention is to provide a system where the engine speed can be adapted to the engine speed corresponding to the vehicle speed and desired gear ratio, where the engine speed both can be actively increased as well as actively reduced, and where a single system is utilized both when increasing the engine speed and when reducing the engine speed. A further object of the invention is to provide a system where energy is conserved during a gear changing process, meaning that energy consumed for retarding the crankshaft in order to accomplish synchronization during a gear changing process can be recovered into a driving torque when the gear has been shifted.
A further object of the invention is to provide a method for regulating the rotational speed of a crankshaft included in an internal combustion engine during a gear changing process of a gearbox connected to the internal combustion engine. In this method, the engine speed can be adapted to the engine speed corresponding to the vehicle speed and desired gear ratio, where the engine speed can be both actively increased, as well as actively decreased, and in which a single system is utilized both when increasing the engine speed and when reducing the engine speed.
Still another object of the invention is to provide a gear changing process for a gearbox arranged at an internal combustion engine where the engine speed can be adapted to the engine speed corresponding to the vehicle speed and the desired gear ratio, where the engine speed can be both actively increased, as well as actively reduced, and where a single system is utilized both when increasing the engine speed and when reducing the engine speed.